Various testing apparatuses for internal combustion engines have been known including those of the in-line system and those of the turntable system.
In the in-line system, each internal combustion engine delivered by a main conveyor is transferred onto a carriage which, in turn, transfers the internal combustion engine to one of separate testing units disposed alongside a circuit as the carriage travels along the circuit. The testing units are installed in separate testing chambers each defined by an enclosure or partition walls, and they individually carry out performance tests with respect to internal combustion engines which have been individually transferred to them from the carriage. As each internal combustion engine has undergone the required performance test, it is fetched onto the carriage which, in turn, is caused to travel along the circuit before the internal combustion engine is delivered onto the main conveyor.
In the turntable system, a plurality of testing units are arranged on a turntable. Each internal combustion engine delivered by a main conveyor is loaded through a carrying-in conveyor or the like onto a carrying-in transfer device which, in turn, delivers the internal combustion engine to a testing unit. The turntable is intermittently rotated so that the required performance test is carried out while the turntable makes one turn. After the performance test is carried out, the internal combustion engine is fetched by a carrying-out transfer device from which it is transferred onto the main conveyor through a carrying-out conveyor.
In either of these systems, testing operation at each testing unit is carried out in such a way that each internal combustion engine is first driven for warming up and then it is subjected to various adjustments in operating conditions, such as idling adjustment, ignition timing adjustment, and exhaust gas adjustment. Further, in this process of testing operation, abnormal noise and vibration measurements and collection of relevant data, such as engine speed, negative pressure, oil pressure, and ignition timing, are made.
Of these known systems, the in-line system, in which internal combustion engines are placed in separate testing chambers for performance tests, has an advantage in that tests can be carried out without noise interference involved between individual internal combustion engines, which permits accurate measurement of abnormal noise and vibration behaviors. Another advantage of the in-line system is that since the testing chambers are stationarily placed on the ground, various data on each internal combustion engine may be obtained as required for entry into a host computer. On the other hand, however, the in-line system has a disadvantage in that one operator is required to look after a plurality of testing chambers with tasks of setting internal combustion engines to individual testing units, conducting performance tests with them, and releasing the engines from the condition of setting, which fact permits no speedy operation and means less operating efficiency. In other words, the number of chambers that one operator can look after is limited and accordingly, when all the testing chambers are operated, a number of operators must be engaged in testing operations. Each operator must be skilled in various kinds of tests involved.
Such disadvantage of the in line system can be overcome by the turntable system. However, the turntable system does not permit accurate measurement of abnormal noise and vibration involved because it is likely to involve noise interference between adjacent internal combustion engines. In addition, the turntable system is disadvantageous in that entry of data into the host computer is not possible except when, for example, the turntable is not in rotation.